Two men have been arrested by detectives investigating the murder of a policeman shot dead during a bank robbery almost 40 years ago.

Inspector Bill Elliott was gunned down as he attended the scene of the robbery in north Belfast in 1974.

The 58 and 61-year-old suspects were detained in Co Antrim on Wednesday morning. They have been taken to the police's serious crime suite in Antrim town for questioning.

Mr Elliott was driving on his own when he heard news that a robbery was under way at the Ulster Bank in the Rathcoole area in September 1974.

The 48-year-old, who was married with a son, raced to the scene and died after a shoot-out with republicans from the Official IRA who were armed with two submachine guns and a pistol.

Mr Elliott was posthumously awarded the Queen's Police Medal.

The original investigation became the focus of controversy when 18-year-old student Ronan Bennett - who is now a high-profile author and screenwriter - was convicted in connection with the killing, despite maintaining his innocence.

He said the evidence against him, from a witness who gave a description of one of the gang, changed a number of times. His conviction was quickly quashed by the Northern Ireland Appeal Court, which cleared his name within a year of the trial.

Detectives reopened the cold case last October and quickly arrested a 57-year-old man. The suspect was later released.